1. Field of the Invention
The present invention relates to an element using a chiral smectic liquid crystal exhibiting ferroelectric characteristics and a display apparatus using the same.
2. Related Background Art
Display apparatuses using ferroelectric chiral smectic liquid crystals are disclosed in, e.g., U.S. Pat. Nos. 4,639,089, 4,681,404, 4,682,858, 4,712,873, 4,712,874, 4,712,875, 4,712,877, 4,714,323, 4,728,176, 4,738,515, 4,740,060, 4,765,720, 4,778,259, 4,796,979, 4,796,980, 4,859,036, 4,932,757, 4,932,758, 5,000,545, and 5,007,716. In each display apparatus of these prior art patents, transparent electrodes are formed on the inner surfaces of opposite glass substrates aligned by rubbing and spaced apart from each other by a cell gap of 1 to 3 .mu.m to constitute a liquid crystal cell, and a ferroelectric chiral smectic liquid crystal (to be referred to as an FLC hereinafter) is sealed in the liquid crystal cell.
This liquid crystal device (panel) is inserted and fixed in a housing and is utilized as a display apparatus. When the liquid crystal panel is mounted using the housing, the upper surface of the housing is higher than the upper surface of the liquid crystal panel. In this arrangement, a display unit of the panel cannot be entirely observed when viewed from an oblique direction. For this reason, a non-display unit having a width of about 5 to 10 mm is formed around the display unit to improve readability of information displayed on the panel.
When a bistable liquid crystal element is used, any signal is preferably applied to this non-display unit to define a non-display unit (i.e., a display frame) for displaying a peripheral portion of an effective display area formed by matrix electrodes in white or black. Since a drive voltage is continuously applied to maintain the display frame in a uniform "white" or "black" display state, durability of the liquid crystal apparatus must be improved.